Bulldozer with adjustable stinger bit



March 8, 1966 D. E. COBB ETAL BULLDOZER WITH ADJUSTABLE STINGER BIT 5 Sheets-Sheet 1 Filed Dec. 23, 1963 INVENTORS.

ATTORNEYS March 8, 1966 5, 055 ET AL BULLDOZER WITH ADJUSTABLE STINGER BIT 5 Sheets-Sheet 2 Filed Dec. 23, 1963 1 INVENTORS.

DELWIN E, CoBB LLOYD K. HEINOLD ATT ORNEYS March 8, 1966 D. E. cows ET AL 3,238,648

BULLDOZER WITH ADJUSTABLE STINGER BIT Filed Dec. 25, 1963 5 Sheets-Sheet 5 INVENTORS.

DELWIN E. COBB "I H BYLLOYD K. HEJNOLD ATTORNEYS United States Patent 3,238,648 BULLDOZER WITH ADJUSTABLE STINGER BIT Delwin E. Cobb and Lloyd K. Heinold, Peoria, 111., assignors to Caterpillar Tractor Co., Peoria, Ill., a corporation of California Filed Dec. 23, 1963, Ser. No. 332,388 2 Claims. (Cl. 37-144) This invention relates to bulldozers and particularly to a bulldozer blade having a portion of its cutting edge adjustable or advanceable downwardly to penetrate the earth while the remainder of the blade is at or above ground level.

Earth working blades on some implements such as earth moving scrapers are provided with a stinger bit or blade portion which extends forwardly or downwardly of the main cutting edge. This reduces the force and traction necessary to move the blade forwardly through hard packed or virgin soil. Such stinger bits have seldom been employed on bulldozer blades because they prevent normal clean up or grading work which are functions of bulldozers after initial pioneering or rough work is complete. The function of a stinger bit is nonetheless highly desirable in bulldozer operations because it enables the making of a reasonably deep cut through material so hard that it overtaxes the tractor engine and tractive ability when the full width of the blade is penetrating the earth. A short blade is also desirable when resistance to cutting is greater toward one end of the blade. For example, in the course of pioneering operations one end of the blade often penetrates the earth more deeply than the other or encounters areas of highly compacted earth or rock. The resulting intermittent loading of an outer end of the blade makes steering difiicult and tends to cause skewing of the tractor from its intended course.

It is therefore an object of the present invention to provide a bulldozer with an adjustable or retractable stinger bit to enable the blade to be used optionally for normal or stinger bit operations.

A further object of the invention is to provide power means controllable by a tractor operator for adjusting the position of such a bit from the operators station.

Further and more specific objects and advantages of the invention and the manner in which it is carried into practice are made apparent in the following specification wherein reference is made to the accompanying drawings.

In the drawings:

FIG. 1 is a view in side elevation of a tractor carrying a bulldozer embodying the present invention;

FIG. 2 is an enlarged end elevation with parts in section of the bulldozer blade shown in FIG. 1 with the stinger bit retracted;

FIG. 3 is a view like FIG. 2 showing the stinger b-it advanced downwardly;

FIG. 4 is a view in rear elevation of the blade and adjustable stinger bit; and

FIG. 5 is a view in front elevation of the blade and stinger bit showing positions of the tractor wheels and advanced stinger bit in broken lines.

The invention is applicable to bulldozers mounted either on track type or wheel type tractors but is shown for purposes of illustration in FIG. 1 as associated with a wheel type tractor of known kind illustrated generally at 10. A bulldozer blade 11 is mounted forwardly of the tractor by means of conventional push arms 12. The

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blade is adapted to be raised and lowered by hydraulic jack means represented at 13 and pitch or tilt of the blade may be adjusted through conventional adjustable tilt braces one of which is shown at 14. The conventional cutting edge of a bulldozer blade which is a hardened plate secured to its lower forward portion is in accordance with the present invention formed, as clearly illustrated in FIG. 5 of three separate portions 16, 17 and 18. The portions 16 and 17 are rigidly secured to the blade itself and the central portion 18, which is preferably approximately /3 of the width of the blade, is adjustable so that it may be lowered to penetrate the earth as illustrated in FIGS. 1 and 3 while the fixed blades 16 and 17 are disposed at or above ground level.

To support the stinger bit for adjustment it is secured to the forward face of a plate 20 carried by a pair of arms 21 pivotally connected as at 22 to pairs of spaced brackets 23 (see FIGS. 2, 3 and 4) welded or otherwise firmly secured to the back of the main bulldozer blade structure 11. Through this construction the stinger bit 18 is disposed for movement between its upper position shown in FIG. 2 where it moves on the same level as the cutting edges 16 and 17 and its lowered position shown in FIG. 3 where it penetrates the earth while the cutting edges 16 and 17 are disposed at ground level. A skid plate 25 is supported by a bracket 26 behind the stinger bit and registers with a conventional skid plate 27 shown in dotted lines in FIG. 3, one of which is disposed behind each of the cutting edges 16 and 17. Consequently when the stinger bit is raised as in FIG. 2 all three skid plates can ride on the surface of the earth in the normal manner for clean-up operations and the like and the skid plates 27 can ride in the same manner when the stinger bit is lowered beneath the surface as shown in FIG. 3. In the position of FIG. 3 earth cut and moved forwardly by the stinger bit will be advanced in the usual manner by the entire blade because of the ground level positions of the cutting edges 16 and 17. The plate 20 is, as shown in FIG. 3, extended upwardly to provide a portion 204: which fills the void between the cutting edges 16 and 17 when the stinger bit is in its lowered position.

In order to adjust the position of the stinger bit any suitable power means may be employed which is capable of adjustment from the tractor operators station. Such power means is herein shown as a pair of hydraulic jacks 28 mounted by trunnions 29 and bearings 30 at the upper end of the brackets 23 and having rods pivotally connected as at 31 with the arms 21. A well known and conventional circuit, not herein shown, may be employed for adjusting the jacks 28 with a control valve at the operators station. The jacks are preferably protected from rock or debris spilling over the top of the bulldozer blade by canopies such as shown at 33 secured to and extending rearwardly from the upper rear surface of the bulldozer blade.

As previously stated the width of the stinger bit is approximately of the width of the entire bulldozer blade but, in any event, should not exceed the space between the wheels or tracks of the tractor upon which the bulldozer is mounted. For example, as illustrated in FIG. 5, where the tractor wheels are indicated at 35, the bit 18 shown in broken lines in its extended position will make a relatively narrow out leaving full traction on firm ground for the tractor wheels.

We claim:

1. In a bulldozer having a blade, said blade having to transversely spaced and aligned cutting edges secured forwardly of the lower edge of the blade adjacent its ends, a third cutting edge in the space between the first cutting edges, and means supporting the third cutting edge for movement between a position substantially aligned with the first cutting edges so as to define a scraper and a lower position for use as a stinger bit.

2. The combination of claim 1 with means movable with the third cutting edge to fill the void between the first two cutting edges when the third edge is used as a stinger bit.

References Cited by the Examiner UNITED STATES PATENTS Dean 37-143 Spoon 37-143 Stout 37-1175 Armington 37-144 Lindberg 37-145 Hoxie 37-145 Cron 37-98 ABRAHAM G. STONE, Primary Examiner. 

1. IN A BULLDOZER HAVING A BLADE, SAID BLADE HAVING TO TRANSVERSELY SPACED AND ALIGNED CUTTING EDGES SECURED FORWARDLY OF THE LOWER EDGE OF THE BLADE ADJACENT ITS ENDS, A THIRD CUTTING EDGE IN THE SPACE BETWEEN THE FIRST CUTTING EDGES, AND MEANS SUPPORTING THE THIRD CUTTING EDGE FOR MOVEMENT BETWEEN A POSITION SUBSTANTIALLY ALIGNED WITH THE FIRST CUTTING EDGES SO AS TO DEFINE A SCRAPER AND A LOWER POSITION FOR USE AS A STINGER BIT. 